<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        * {
            margin: 0;
            padding: 0;
        }

        .main {
            width: 50%;
        }

        div {
            float: left;
            margin: 16px;
        }

        p {
            text-align: center;
            border: 1px gray dashed;
        }
    </style>
</head>
<body>
<div class="main">
    <div>
        <img src="http://climg.mukewang.com/590fe9770001e63102400135.jpg" alt="">
        <p>欢迎来到imooc</p>
    </div>
    <div>
        <img src="http://climg.mukewang.com/590fe97d00011bda02400135.jpg">
        <p>欢迎来到imooc</p>
    </div>
    <div>
        <img src="http://climg.mukewang.com/590fe982000150ba02400135.jpg" alt="">
        <p>欢迎来到imooc</p>
    </div>
</div>
<div class="main">
    <div>
        <img src="http://climg.mukewang.com/590fe9770001e63102400135.jpg" alt="">
        <p>欢迎来到imooc</p>
    </div>
    <div>
        <img src="http://climg.mukewang.com/590fe97d00011bda02400135.jpg">
        <p>欢迎来到imooc</p>
    </div>
    <div>
        <img src="http://climg.mukewang.com/590fe982000150ba02400135.jpg" alt="">
        <p>欢迎来到imooc</p>
    </div>
</div>
</body>
</html>